Substituted phenothiazines

ABSTRACT

NEW ALKYLATED PHENOTHIAZINES ARE USED AS STABILIZERS FOR ORGANIC MATERIALS. THE COMPOUNDS ARE PREPARED BY ALKYLATING PHENOTHIAZINE.

United StatesPatent Of ice r I 3,803,140 suasn'wnn PHENOTHIAZINES Cook; Fllxtou, near Manchester. and Donald Richard Randell, Stockport. England, assignors to Ciba- Gcizy'Corporatlon, Artlsley, N.Y. w 7 Nu Drawing. Filed Mar. 2, 1972. Ser. No. 231,390 Claims priority, application Great Britain, Mar. 12, 1971,

6,727/7L Int. Cl. C071! 93/14 US. Cl. 260-443 A I ABSTRACT OF THE DlS LOSURE New al kylated phenothiazines are used as stabilizcrs'for Organic materials. The compounds are prepared by alkyl- 6 Claims ating phenothiazine;

'lhef present invention relates to new chemical compounds and .in particular to alkylated'phenothiazines useful as antioxidants for organic materials.

According to'the present invention, there is provided a substituted phcnothiazine of the formula:

wherein R'lis hydrogen; alkyl or alkenyl each havingtirom 2 to 12 carbon atoms; cycloalkyl having from 5 to 12 carbon atoms;:-;aralkyl haying from 7 to '9 carbon "atoms; cyauoallryl or-hydroxy-alkyl each having from 2 to 4 carbon atoms; or the group YOCH;--- wherein Y is an ethyl radical having from i to 4 carbon atoms or n cycloalkyl residue having from 5 to't2 carbon atoms; R is alkyl havingifrom 1. to 4 carbon atoms R is methyl; R is a phenyl residue either unsubstitutcdo'r substituted with from 1 to 3 'alkyl substitucnts each havingfrom 1 to 4 carbon atpmsrorcR, and R together'withthe carbon atom to which thcyare bound form a rnono-cyclic ring system having from "5 to l2 carbon atoms win the ring which is preferably unsubstituted or has from 1 to 3 alkyl su'bstituent-groups each having from 1 hi4 carbon atoms;

m is 0 or Because of their case of preparation and their high level of stabilizing activity in organic material, compounds of. Formula I are preferred in which R is hydrogen.

When the 'roup 'R is all ryl, this may be isoamylyn-hexyl, n-heptyl; n-octyl, t-octyl or n-dodccyl but R is preferably a C1-C4 alkyl lgroup such as methyl, cthyl isopropyl, n-propyl or n-butyl; when R- isa nikyl it maybe benzyl; when R is alircnyl, it may befl/ior ap-dimethallyl or dodecenyl althoughpreferred aikcnyl groups are C2-C4 alkenyl groups suchas ally] or a-mcthullyl; cyanoalkyl and hydroxyalkyl groups are preferably cynnoethyl and hydroxyethyl and preferred 'alkoxymcthyl groups are 1 the methoxymethyl, the ethoxymcthyl and cyclohexyloxy methyl groups. 1

When R; and R; together with the C atom to which they are attached form a mono-cyclic ring, such rings are saturated rings; preferred instances of such cyclic groups include cyclohexylidene; 4-isopropylcyclohexylidenc and cyclododeeylidene. Examples of compounds of Formulalincludci 3:7-diin,a-dimethylbenzyl)phenothiazine 317'dilmmfl trimcthylbcnzyi)phenothinzine 3 2 7-di f u,-cthyl-ocmethylben2yl phenothinzine 3 7-diia-n-butyi-wrncthyl benzyl phenolhiaziric- J \vlurcin R R R, and m havc l'hcir previous significance.

recanted Apr.-9, i974 10-rnethyl-3 7-di l methylcyclohexy'l phenothiazine ]0 -u-butyl-3 7-di( l methylcyclohexyl)phcnothiazine l0-n-dodecyl-3 7-di'( l-methyleyclohexyl) phenothiazine IO-mcthyl-l :3 7-tri(a,e--dimethylbenzyl)phenothiazine 10-benzoyl-3 7-di l'-mcthylcyclohexyl phenothiaiine 10-ally1-3 7-di(a,a-dimethylbenz'yl )phenothiaz'ine lO-cyclohcxyl-3 7-dil a-dimcthylb enzyl )phenothiazine thiazine I l0-fl-cyun0elhyI-3 :7-di( l-methylcyclohexyl)phenothiazine IO-p-hydroxyethvl E 7-di ;a-dimethylhenzyl)phenn thlazine lO- methoxymethyl-3 7-di( u,m-dimethylbenzyl) P148110? thiazine l0eth0xymeth'yl-3z7-di(a,a-dirnethylbenzyl)phenothiazine I IO-cyclohexoxymethyld 7-di(a,a-dimelbylbenzyl phenothiazine thiazine thtazme v l0-cyclohekoxy-3 7-di(l'-rnethylcyeloheiryl)phen0 Particularly preferred compounds are I I I 3:7-di(q a-dhnethylbenzyl)phenothiazine 1:3 :7:tri(n,u-dimethylbenzyltlphenothiazine 3:7'di l'-methylcyclohexyl)phenothiaiine The present invention also provides a process in which a compoundof Formula I is produced comprising reactmg phcnotlnazme with the corresponding olcfine or alcohol, in the presence of an acid catalyst to produce a compound of formula:

- lit r m l, v

ngca Y 0 R, 7

n. H, m m rm optionally convertingcompound of Formuln ll into the corresponding N-ulknli melnlfsall. rind-then reacting this unit with the corresponding ulkyl, cycionlllyl, ulkcny'l or arnlkyl halide, ll) product at Compound ofl ormula l in which it is an nlkyl, cyulonliiyl, lilltcnyl orurulkyl radical.

317-di-substilutcd pltenothiaz nes are the principle productspl' these alkylation reaction; but they may be accompanied by l:3,7-Il'i-Subslitutcd phcnothiazincs or even B-moncysubstitutiad phenothiazines. thus using a methyl styrene in the alkylation the main product is 3:7- di-substituted phenothiazines but l:3,7-lri-substitutcd phenothiazincs can also be isolated using for instance,

tcchnt'quessuch as chromatography or fractional crystah lization. Mixtures containing two or more of the mono-,

diand tri-substituted l I antioxidants for organic material without impairing the excellent 'antioxidant activity of the di-substituted derivatives. Moreover, such mixtures may be used as starting materials in' N-substitution reactions.

The ring alltylation step of the process is preferably effected by adopting the procedure described and claimed in British patent specification No. l,036,696. Suitable olefines or alcohols for use in this stage include a-mcthyl styrene, a,4 dimcthylstyrcnc, a-mcthyl-4-isopropylstyrenc, l-methyl cyclohexcne, or I-mcthyl -substitution reaction stage, a suitable alkyl halide is butyl bromide, allyl bromide is a suitable alkcnyl halide and benzyl chloride is a suitable aralkyl'halidc.

products may he used. di ectly as, I

cyclodccanol. In the Rust inhibitors which may be cmployed in the lubricant? his ttrilluoracctylacetonates); V the mono sodium salt of the (c) for lead; for example quinizarin, propyl gallate,

scbncic acid etc.

compositions include those of the following groups:

-If R in the compound of Formula I is a .cyanoalkyl group, the compound of Formula II may helreactcd with the corresponding cyano olefine, for instance acrylonitrilc, preferably in the presence of a basic catalyst, for instance trimethylb'enzyl ammonium hydroxide. In order to obtain a compound of Formula I in which R is alkoxymethyl, or cycloalkoxymethyl. N-alkoxymethylation or N-cycloalkoxymethylation of the compound of Formula Il may be'cffcctcd using a mixture of formaldehyde with the appropriate alcohol, sodium dihydrogcn phosphate. N-hydroxyalltylation of the compound of Formula II by reaction with the appropriate olefine oxide, for instance ethylene oxide or propylene oxide.

The compounds of Formula I have useful stabilizing materials. 7

The present invention also provides therefore a composition comprising an organic material and a minor proportion of a compound of Formula I.

The composition preferably contains a proportion of the compound of Formula I within the range of from 0.001% to 5.0% by weight, more-preferably within the range of from 0.1% to 4.0% by weight, based on the Weightoflthcprganicmateriul.

Compounds of Formulal are particularly effective as which thc organic material is a lubricant. Such-lubricant compositions may contain as well as the compound of Formula l, antio. tidants, metal complexants, metal pnssivators, rust inhibitors, viscosity-index improvers, pour-point depressants, dispcrsants or detergents, extreme pressure or anti-wear additives.

Examples of suitable antioxidants are compounds or may be achieved for cxamplc preferably in the presence of.

mixtures of compounds selected from one or more of the I following groups:

(i) alkylatcd and non-alkylated aromatic amines and mixtures thereof (ii) hindered phenols (iii) alkyl, aryl or alltaryl phosphites fiv) esters ofithiopropionie acid I (v) salts ofdt-thio carbamic or d thtophosphor c acids I Suitablciamine, compounds ttndcr sub-heading (i) are dioctyldiphenylamine, monot -octyl-nand tt-nnphthylamines, dloctjil-phenothiazine and g-phcllyl-uand it naphth'ylamine;suitable hindered phenols tinder. sub-heading (it) are 1,6-di-tertiarybutyhp-crcwl, 4 4-bls-(2.6-dilsopropylpheiibl j,

bis-(4-triethyl-o ttbutylphenoly; examples of. phosphitcs undcrlteatlififgtiiil are triphetiyl phosphitc, trinouyl phosphitc nnd diphenyitlecylpho iphite; a suitable ester ofjthiodiptopionio 'acid is dilauryl th-iodip'rt'ipionatc, examples ol tit for instance, substanccs ialling.within the following '(d) Sulphur containing materials, for

' lubricant. This advantage is ly since aviation (a) Organic acids for instance, scbncic acid and N-oleyl,

sarcosinc and-esters,-.mctal salts and anhydrides of organic acids, for example, sorbitan mono-oleatc, lead naphthenate and dodeccnylsuccinic anhydridc. (b)-=Nitrogen containing materials, for example I (i) rimary, secondary or tertiary aliphatic or cyclo aliphatic amines and amine salts of organic and in organic acids, for example morpholine, stearyl amine and triethanolnmine caprylate.

(ii) hetcrocyclic compounds, for example imidazolines, and oxnzolincs.

'(c) Phosphorus containing materials, for cxample'inorganic phosphates, phosphonic acids and aminevphosphatcs. I

example barium dinonylnnphlha'lcnc sulphonates, Suitable viscosity indcximprovers or SZtl'tlS arc, tor instance, polya'ct'ylates,

inyl pyrrolitlones and polyc'tliers.

Iixnmples of dispcrsants or detergents include metal sulphonates especially Calcium, barium and magnesium Salts, metal phcnatcs and polybutcuyl succinimides.

Extreme pressure or antiwcnr additives appropriate for 3 use in the lubricant composition include sulphur and/or chlorinated paraftins. N

'lhe new compounds of Formula I exhibit excellent nll-round antioxidant properties in synthetic lubricants. However a particular advantage which-these compounds possess over other phenothinzine compounds previously described as antioxidants for synthctic lubricants is that I they do not lead to the formation of insoluble matterduring oxidation while in application or on storage of the clauses in their specifications for synthetic tended for use in aircraft engines.

Other organic materials susceptible to oxidati e degrad'zttion and forltrhich the" compounds of Formulnl'of tltc present invention are valuable antioxidants include,

groups:

synthetic polymers derived from condensation reactions containing clltct ester, ami lcflor urethane groupings,

' for in tance polyester,

V pt'.ily.'imide, polyurethane and. ,polyaiiyit;tit: clhet'rc ins. M"

pour point deprespolybutcnes, polyof great importance, especial authorities now stipulate storage stability lubricants in-l polymeric materials, for in (c) oxygenvcontaining for instance aldehyde: such as wheptalde'hyde, and nnsatw ratedf'tauy acids or ester thereafter instance ricinole ic ncidfand 'methyloleate (d).or gano metalioid substances such as' silicone poly met: for instance polydimet'hylsiloxanes. polymethylphenyl-siloxnnes and chlorinatedderivatives thereof,

I To ate s satnple. am as mat. means- We; the tes 4.0% by am or n '3zl-dt-tq-diantioxidantslnre summarized'in'th'e 'lable I.

Titans;

and organometallic substances such as organo-metallic polymers. I (e) .vitamins, essential oils, ketones and ethers.

Some "e iiamples will now be given; parts by weight 'shown therein bear the same relation toparts 'by volume as do'kilograms to litres.

EXAMPLE 1 118 parts by weight of a-methylstyrene were dissolved in 350 parts by volume of petrol ether (boiling range 100 to 120 C.). 80 parts by volume of this solution was added to a mixture of 99.6 parts by weight of phenothiazine and 9.5 parts by weight of p-toluenesulphonic acid. The. mixture was heated toreflux in a nitrogen atmos-,

phere and the remainder of the a-methylstyrcne solution .i

added over a period of two hours at the reflux with stirt. the mixture then being stirred. at reflux for further 4 hours. 40

pension so formed was stirred for IS-minutes at 95 and the aqueous layer again removed.

The petrol phase was washed with water (6x250 parts by' volume) until neutral. and the washed solution left to cool with stirring. n standing 116 parts by weight (52% theory yield) of crude 3z7 di(a,a-dimethyibenzyl) phenothiazine was obtained. Recrystallization from petrol (boiling range l00-l20 (3.) gave pure material having melting point 131.5 to 132.5 C. and the following elemental analysis by Weight:

Found(percent): Carbon, 82.97; hydrogen, 6.82; ni-

trogen, 3.1 l; sulphur. 7.56. Calculated for C H NS (percent): Carbon, 82.76; hydrogen, 6.66; nitrogen, 3.22; sulphur, 7.36.

EXAMPLE 2 A synthetic ester-based lubricant was formulated and subjected to a sliz'htly modified Pratt and Whitney Type ll oxidation-corrosion test. The hasejluid was a complex I ester derived from sebacic acid, capry'lic acid and trit'nethylol propane, the complex ester being dcaot'ibed and" claimed in British patent specification Not 97l,)0l.

Each test was carried out for 48 hours at a temperature (it 425" F'Jttning. dry air at a rate of litres per hour and in the presence of specimens of titanium, aluminum alloy, copper, silver and steel.

t v Acid V r Percent] value g Percent viscosity increase Sludge eight-changes in specimens, tngJcmJ', additive. tut-reuse, (nut. mgJtOO v y Example"; k Additive. by Wt. 103" F. KOll/rz). ml. 'Il I Al Cu Ag Steel Plienothinzlne... 2.0 Q

I gfif i r m I 2 3} 11.9 2.7 1.850 +0.34 +928 +9.34 +0.39. Ft-0.31 I -t-0ety ieno tazne.

yfi t fli li I TI I :1 20.9 13.9 La 0.0a 0.0; 0.41 I not 0.9a

: mll my item inunit. y x t 28.2 9.2 a1 +0J0l +0.01 -o'.ui' .,-o.o2 -o.oa Benguthrlamlr- 0. V H

silaues for.instance tetra-alkyl and tetra-aryl silanes; EXAMPLE 3 parts by."wcighf'of*lFmethylcycIQheXene wereidissolved in 175 parts by volume of petrol ether (boiling range 100 C. to 120 C). 150 parts by'volume ofthis solution was added to a mixturof 49.8, parts-by weightof phenothiazine and 4.8 parts by weight of p-toluene sulphonic acid. The mixture was heated to reflu XTin a nitrogen atmosphere and the remainder of the l-methylcyclohexene-solution addedover a period of 2 hours at the'rellux with stirring. the mixture then being stirred-at refiux for a. fl'tthtfl l6 hours. 1' I Without COJllnll. '50 parts by volume of 10% (w./v.')1.

aqueous NaOH so -tion were added to the mixture over a period. of i5 minutcs-thtemperaturc being maintained at C. The color of the mixture went from deep purple to green; the aqueous phase .wns'syphoned from the-mixture and the-petroleum ether solution was left to cool to room temperature. Thesolid-thus produced was filtered and-:washe'd with water (5X 250 parts by volume) and petrol ether (boiling range 40 to 60 C.). L';ln';this way, 59 partsby weight (60% theoryyield) of crude 3,7-di- (l'-mcthylcyclohexyl) phenothiuzincwere obtained.

Recrystallization from a mixture of equal parts by volume of petrolether (boiling range to C.) and petrol ether (boiling range 60 to 80 C.) gave pure mafollowin'gelementul analysis by weight;

Found=(pei'cent): C. 79.79; H. 8.222-N. 3 .59. Required for C H5 NS (percent): (3.79.74: H, 8.49; N; 3.57.

EXAMPLE 4 t terial having a melting point of 138 to l40 and the parts by volume of chloroform. thus precipitating a srnallv amount of' polyacrylonitrile. this was removed byifiltration and the filtrate was stripped of solvent. to give crude l0 ti cyanoetlryl-JJ-di-( a-dimcthylbenzyl) phcnothiazirtc. Recrystallization trom c'thyl alcoholgavc 2.2 g. of

hpure material (22.5% of theory yield) melting at (Land having the following elemental analysis:

Found (percent): C. SLOB; it-6.62: N. 5.-5l; S. 6.7

- To a solution of 21.8 parts hy weight of 3.7-di (-a.a

ditnethyihenz'yl) pheuothiazine and 12.8'parts hy'weig'hl of heuzylchloride in 250 parts hy volume of tolucuc'tpro viously dried by nzeotropic distillation hv means of a;

Dean and Stark uppiuatus), there was added"tflparts l y.

weight of powdered sodium hydroxide. The resuiting'sue pension was heated at reflux, uitli'stitriug for 36 hours,

during which time water, during the reaction, I

was removed by azeotroptc distillationdqean and Stark t apparatus).

The cooled suspension was then taken and the insoluble material removed by filtration. The filtrate wasstripped of sol cut to give a solid, which by recrystallization from Cellos'olvegave 17.8 parts by weight of pure .l0-benz'yl- 3,7-di- (d,a'-ditnethylbenzyl) phenothia'zine (57%" 'of theory yield), melting at l55" C. and having the following elemental: analysis:

addition of 150 by volume of petrol ether (boiling I range lOO to 120 C.) at 95 C.-The aqueo i s phase was r syphonedfrom the mixture and a"furt'her"l00 parts by volume of loft: weight/volume of aqueous sodium hy-L droxide solution were added to the petrol-fractionr 'lhe- 1. suspension so-formcdw'as stirred for 15 minutes at 95' C.

and the aqueous layer wasagairtrernoved,

'1 parts by volume) to neutrality and the washed solution" Found (percent): C, 84.59; H, 6.92; N, 2.44; S, 5.91.

Required for C5 H NS (percent): C, 84.54; H, 6.71; N, 2.66; S, 6.09. EXAMPLE 6 2.2 parts by, weight of 3.7-di-(a,ut-dimethylbenzyl) phenothiazine,"0.5 part by weight of sodium dihydrogcn' phosphate and 100 parts by volume of ethyl alcohol were heated to reflux, 10 parts by volume of 37% aqueous formaldehyde solution were then added and the resulting suspension was ..heated at reflux for a further four hours. The suspension was then filteredhot and the white solid EXAMPLES 7, 8 AND 8A A complex ester derived from sebacic acid, caprylic acid and 1:1:l-trimethylol propane (produced according to the procedure described in British patent specification No. 971,90l) was diluted with lzlzl-trimcthylol propane tricaprylate to give a mixture having a viscosity of 7.0 centtstokes at 2l0 F. Air saturated with water was then passed through 50 ump!- of esters containing 4.0% by weight of 3,7-di-(a.a-dimethylbenzyl).

phenothiazine (Example 7) and 4.0% by weight of 3:7-di- (l'-methylcyclohexyl) phenothiazine (Example.8) at 100 C. over a period of 192 hours. The lubricant samples were inspected visually for the presence of insoluble matter. No insoluble matter was apparent at the end of this oxidation stage.

The lubricant samples were then transferred to a cupwas noted at the end of the oxidation stage.

EXAMPLE 9 l 18 parts by weight of a-mcthylstyrcnc were dissolved in 350 parts by volume of petrol ether (boiling range 100. lo l20 C.), and 80 parts by yolume ofthis solution were added to a mixture of 99.6 parts by weight of phenothiazine and 9.5 parts by weight of p-toluene sulphonic acid. The mixture was heutedunder reflux conditions under a nitrogen atmosphere and the rcmainder of the e-methylstyrene solution was added, with stirring, over a was left to cool while being stirred. On standingyllib parts by weight (52% vtheoreticalyield) of crude 3.,7di- (a,a-dimethylben2yl) phenothiaziiie were obtained.

"Evaporation of the petrol/mother liquor" gave a stic l ty darlt'green residue which was chromatographed on basic alumina, by elution with a 10% SOlUliOttfOf diethyl ether in petrol i(boiling range 60" to 80 C.)', to give 1,3,7- tti(tm-dimethylbcnzyl") phenothiazine as a cream col ored glassy material havingthe following elemental analysis by weight:.

Found (percent): Carbon, 84.52; hydrogen, 7.30; nitrogen, 2.30; sulphur, 5.62. Calculated for C HQ NS (percent): Carbon, 84.59; hydrogen, v7.l0; nitrogen, 2.53;

sulphur, 5.78.

. EXAMPLE 10 19.9 parts by weight of phenothiazine and 1.9 parts by weight of p-toluenc sulphonic acid were suspended in l parts by volume of petrol'eum'ether (boiling range 100- 120 C.').. This mixture was thcn heated at reflux, with stirring, under an atmosphere of nitrogen and a solution of 26.4 parts by weight'of a-4-dimethylstyrene in 80 parts by weight of petroleum ether (boiling range 100-120 C.) was added over a period of 2 hours, the resulting soitt ion was then heated at reflux for a further 3 hours.

The solution was then cooled to approximately C. and washed with 10% aqueous sodium hydroxide solution in 3x 100 parts by volume amounts to give a pale green solution which onstanding at room temperature for 8 hours gave a pale reen precipitate of crude 3.7-di- (a,a,4-trimethylbenzyl) phcnothiazine which, after "recrystallization from petroleum ether (boiling range C.) gave 8 parts by weight of pure material (17% theory yield) melting at 126 C. and having the following elemental analysis by weight:

Found (percent): C, 83.09; H.738: N, 2.80; S, 6.80. Calculated for C HQNS (percent): C, 82.9; H, 7.17; N, 3.02; 5.6.90.

EXAMPLE ll 21.8 parts by weight of 3,7-(di,ot.u -dimethylbcnzyl) phenothiazine and,3.7 parts by weight of sodamide (finely ground) in parts by volume xylene were heated at reflux, with stirring for 20 hours. To the resulting suspension was added 13.7 parts by weight of n-butyl bromide octyl phenothiazine. the formation of insoluble material period of two hours at relittx,'thc mixture being then stirred at reflux for a further four hours.

Without cooling, 100 parts by volume of 10% weight/ volume aqueous sodium hydroxide solution was added to the mixture. Over a period of fifteen minutes the color of the mixture changed from deep purple to green and it precipitate was formed. 'lhis solid was dissolved hy the at reflux over 15 minutes. The mixture was then heated at reflux for a further 3 hours when it was cooled and the xylene distilled off under reduced pressureto give a viscous oily product, which by repeated recrystallization from petroleum ether (boiling range 60-80 C.)'gave 1:5 parts by weight (6% theory yield) of pure l0-n-butyl- 3.7-di-(a,a-diniethylbcnzyl) phenothiazine melting at 147 C. and having the following elcmental'analysisby weight:

Found (percent): C, 82.74; H, 7.72; N, 2.96. Calculated for C H NS (percent): C, 8 3. l; lit-7.54; N,'2.86.

EXAMPLE i2 7 8.7 parts by weight of 3,7-di-(ma-dimethylbeniyl) phenothiazine and 1.8 parts by weight of finely ground sodamitle in 100 parts by volume'of dry xylenewere heated at reflux. with stirring, for 5 hours. 4.8 parts by weight of allyl bromide were added to the resulting suspension, at reflux. over 15 minutes. Themixture was I then heated at reflux for a further 3 hours and then cooled and the xylene removed hy 't'lislillation ttntlc'r reduced pressure. A vi cous oily product was obtained which, when tritutated with petroleum ether (boiling W mm at range QDY -SU' C.) gave a dark green solid. This solid was continuously extracted with petroleum ether (boxiing range 40"60' C.) to give 1.2 parts by weight l 15% benzyl) phenothiazine having matting-point 128 12? C. and the following elemental analysis by weight:

Found (percent): Carbon, 83.63; hydrogen, "6.99

nit ogen. 2.55; sulphur. 6.77. Calculated for C H NS (percent): Carbon, 83.36; hydrogen, 6.94; nitrogen, 2.94; sulphur, 6.73.

EXAMPLES 13 TO. !6

Synthetic lubricant. formulations were made up and tested under the'coudilions of Federal Test Method Standard No. 791 a (VV-L-79la) Method 3462 dated;-

under test details of which are shown in the folioiving Table U. Each lubricant was mechanically splashed against. an aiuminium plate maintained at 609 F. for;-

Tiie cokiug.,values are also set out in the following Table HA and H8.

TABLE HA.

Coke 1 depo it Example Antioxidant. (mg-i N-benzyhBJ-dktoctyltphciinthhzlne ails l3. 3,7-di( a-dimethyllmnzyl)ph nothiazine..-" 21.3

These results demonstrate, iii-terms of coi ze depositiom the ciear superiority of the iubricant containing, as antioxidanL-a'tompound of the invention as compared with a The mans in 'lablc llB Show that when a pheuolhiazine '5 antioxidant is combined with a; known amine antioxidant,

a period of 8 hours, the amount of coli' deposited on the-panel being determined at the end of the test period.

lubricant. the results achieved are much superior to We claim: j I. A compound having formuia' 2 to 12 carbon atoms, cycloalkyl having from" 5 to 12 .carbon atoms, aralkyl having from 7 to 9 carbon atoms,

cyanoalkyl or hydroit yalizyl each having from 210 4carhon atoms, or the group YOCH WhereinIY an alkyl radical having-from ito 4 carbon atoms or a cyclol slitttent groups'e'ach having from 1 to 4 carbon atoms;

"and m is 0 to l.

- 2. A compound as claimed in claim iWherein R is H, m is l and R R: ard Rg are asdefined in claiml.

3. A comnound as claimed in claim 1 wherein R is H,

' m .is 0 and R R; and R areas defined in claim 1.

fat

and the combined antioxidant is evaluated in a synthetic 5. A compound as claimed in claim 1, which'is 1:3:7-

' 6. A compound as claimed in claim 1, l'-methylcyclohcxyl pbenothiazine.

References Cited 1 UNITED snares PATENTS 3.376.224 4/1968 tannin ct at. 260-443 3.489.749 1/1970 Randeil 260-7243 3,539,515 11/1910. McCabe 260-243 FOREIGN PATENTS- 1,036,696 7/1966 England 260-243 nanny 1. MOATZ, Primary Examiner us. Cl. x11.

7 12,398 R, Gtt'R, 8:4, 860; 252-402, 405 1 obtained using btends of knoan phenothizzine and known V .arnine antioxidants. theoretical yield) of pure IO-allyl-JJ-di-Kmu-dimethgrlv tn wherein R is hydrogen, alkyl or alkcnyleach having from which is 354i- 

